1. Field of the Invention
The present invention relates to a tire noise reducing system capable of reducing a road noise caused during driving of a vehicle, and more particularly, to a system having a noise damper disposed in a cavity.
2. Description of the Related Art
A road noise is known as one of tire noises. The road noise is a sound around from 50 to 400 Hz generated from a tire running on a road surface. A cause of the road noise is resonance vibrations of air generated in the tire cavity. In recent years, there is proposed a tire noise reducing system comprising a tire (b), a rim (c) on which the tire is mounted, and a noise damper (a) disposed in a cavity surrounded by the tire (b) and the rim (c) as shown in FIG. 8(A).
The noise damper (a) is made of porous material. The noise damper (a) absorbs vibrational energy generated in the tire cavity, suppresses the resonance and reduces the road noise. The noise damper (a) is fixed to the cavity. When the noise damper (a) is not fixed to the tire cavity, the noise damper a collides against the tire (b) or an inner surface of the rim (c) and is destroyed due to a centrifugal force and lateral force when a vehicle runs, and thus it can not suppress the resonance noise. That is, in order to maintain the noise reducing effect for a long term, durability of the noise damper is desired. Even if the noise damper is fixed to the tire cavity, however, the noise damper is damaged in some cases.